Molecular level damages of low power pulsed laser radiation in a marine bacterium Pseudoalteromonas carrageenovora

Nandakumar, Kutty Selva; Obika, Hideki; Utsumi, Akihiro; Ooie, Toshihiko; Yano, Tetsuo

doi:10.1111/j.1472-765x.2006.01897.x

Cited by 9 publications

(5 citation statements)

References 23 publications

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“…The reason for the difference in the mortality rates in these two types of radiation is undoubtedly due to the difference in the mechanisms of action these types of radiation have on the microbial cells. Visible laser light in the low power region results in the generation of reactive radicals (Wilson, 1993), and might result in the breakage of cell walls and generation of apurinic-apyrimidinic sites in the bacterial DNA (Nandakumar et al, 2005). These changes would lead to cell damage and death.…”

Section: Discussionmentioning

confidence: 99%

Visible laser and UV‐A radiation impact on a PNP degrading Moraxella strain and its rpoS mutant

Nandakumar

Keeler

Schraft

et al. 2006

Biotech & Bioengineering

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The role of stationary phase sigma factor gene (rpoS) in the stress response of Moraxella strain when exposed to radiation was determined by comparing the stress responses of the wild-type (WT) and its rpoS knockout (KO) mutant. The rpoS was turned on by starving the WT cultures for 24 h in minimal salt medium. Under non-starved condition, both WT and KO planktonic Moraxella cells showed an increase in mortality with the increase in duration of irradiation. In the planktonic non-starved Moraxella, for the power intensity tested, UV radiation caused a substantially higher mortality rate than did by the visible laser light (the mortality rate observed for 15-min laser radiation was 53.4 +/- 10.5 and 48.7 +/- 8.9 for WT and KO, respectively, and 97.6 +/- 0 and 98.5 +/- 0 for 25 s of UV irradiation in WT and KO, respectively). However, the mortality rate decreased significantly in the starved WT when exposed to these two radiations. In comparison, rpoS protected the WT against the visible laser light more effectively than it did for the UV radiation. The WT and KO strains of Moraxella formed distinctly different types of biofilms on stainless steel coupons. The KO strain formed a denser biofilm than did the WT. Visible laser light removed biofilms from the surfaces more effectively than did the UV. This was true when comparing the mortality of bacteria in the biofilms as well. The inability of UV radiation to penetrate biofilms due to greater rates of surface absorption is considered to be the major reason for the weaker removal of biofilms in comparison to that of the visible laser light. This result suggests that high power visible laser light might be an effective tool for the removal of biofilms.

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Section: Discussionmentioning

confidence: 99%

Visible laser and UV‐A radiation impact on a PNP degrading Moraxella strain and its rpoS mutant

Nandakumar

Keeler

Schraft

et al. 2006

Biotech & Bioengineering

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“…Histopathological analysis showed that the levels of infection and the bacterial count decreased significantly in the treated groups. According to Nandakumar et al [11], bacterial killing is related to cell wall damage and genetic material, reducing bacterial adherence and preventing biofilm formation [10]. Karu [32] relates the cytotoxic action to the production of highly reactive molecules that cause membrane rupture and subsequent bacterial death.…”

Section: Discussionmentioning

confidence: 99%

“…This physical feature has helped in controlling chemical mediators that play an important role in generating the inflammatory process, such as reduced expression of COX-2 [4], decrease in concentration of prostaglandin E 2 (PGE 2 ) [5], analgesia by the peripheral release of endogenous opioids [6], and edema reduction and anti-inflammatory action probably due to the release of adrenal hormones [7]. However, the use of lasers in the presence of an infectious process has not been well elucidated in the literature, as there is still a controversy regarding low-power laser on bacterial growth, concerning its parameters of use, such as wavelength, power, irradiation dose, type of laser, and effects on different bacterial strains [8–11]. Thus, although some studies show innocuous in relation to the increase of bacterial colonies subjected to laser application [12, 13], others demonstrate bactericidal and/or bacteriostatic effects [11].…”

Section: Introductionmentioning

confidence: 99%

“…However, the use of lasers in the presence of an infectious process has not been well elucidated in the literature, as there is still a controversy regarding low-power laser on bacterial growth, concerning its parameters of use, such as wavelength, power, irradiation dose, type of laser, and effects on different bacterial strains [8–11]. Thus, although some studies show innocuous in relation to the increase of bacterial colonies subjected to laser application [12, 13], others demonstrate bactericidal and/or bacteriostatic effects [11]. There is also the contradiction of the experiments that found an increase in bacterial growth [14].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Low-Level Laser Therapy, 660 nm, in Experimental Septic Arthritis

et al. 2013

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The effectiveness of low-level laser therapy (LLLT) in the presence of an infectious process has not been well elucidated. The aim of the study was to evaluate the effects of LLLT in an experimental model of septic arthritis. Methods. Twenty-one Wistar rats were divided as follows: control group, no bacteria; placebo group, bacteria were inoculated; Treated group, bacteria were injected and treatment with LLLTwas performed. To assess nociception, a von Frey digital analgesimeter was applied. Synovial fluid was streaked to analyze bacterial growth. The standard strain of S. aureus was inoculated in the right knee. LLLT was performed with 660 nm, 2 J/cm2, over 10 days. After treatment, the knees were fixed and processed for morphological analysis by light microscopy. Results. It was found that nociception increases in the right knee. There was a lack of results for the seeding of the synovial fluid. The morphological analysis showed slight recovery areas in the articular cartilage and synovia; however, there was the maintenance of the inflammatory infiltrate. Conclusion. The parameters used were not effective in the nociception reduction, even with the slight tissue recovery due to the maintenance of inflammatory infiltrate, but produced no change in the natural history of resolution of the infectious process.

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“…In the field of cultural heritage, it is a well established technique, allowing fine and selective removal of superficial deposits and encrustations [10,[13][14][15][16][17][18][19][20][21][22][23][24][25]. Laser irradiation can be used for antifouling purposes, causing mortality to biofilm forming microorganisms, like marine bacteria and microalgae [26,27]. When applied to the treatment of lichen encrustations on stone, and although laser cleaning fails to completely remove lichen thalli, superficial lichen debris can be brushed away without affecting the substrate surface [10,28,29].…”

Section: Introductionmentioning

confidence: 99%

Influence of wavelength on the laser removal of lichens colonizing heritage stone

Sanz

Oujja

Ascaso

et al. 2017

Applied Surface Science

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Laser irradiation of lichen thalli on heritage stones serves for the control of epilithic and endolithic biological colonizations. In this work we investigate rock samples from two quarries traditionally used as source of monumental stone, sandstone from Valonsadero (Soria, Spain) and granite from Alpedrete (Madrid, Spain), in order to find conditions for efficient laser removal of lichen thalli that ensure preservation of the lithic substrate. The samples presented superficial areas colonized by different types of crustose lichens, i.e. Candelariella vitellina, Aspicilia viridescens, Rhizocarpon disporum and Protoparmeliopsis muralis in Valonsadero samples and P. cf. bolcana and A. cf. contorta in Alpedrete samples. A comparative laser cleaning study was carried out on the mentioned samples with ns Q-switched Nd:YAG laser pulses of 1064 nm (fundamental radiation), 355 nm (3rd harmonic) and 266 nm (4th harmonic) and sequences of IR-UV pulses. A number of techniques such as UV-Vis absorption spectroscopy, stereomicroscopy, scanning electron microscopy (SEM), SEM with backscattered electron imaging (BSE), electron dispersive spectroscopy (EDS) and FT-Raman spectroscopy were employed to determine the best laser irradiation conditions and to detect possible structural, morphological and chemical changes on the irradiated surfaces. The results show that the laser treatment does not lead to the complete removal of the studied lichen thalli, although clearly induces substantial damage, in the form of loss of the lichen upper cortex and damage to the algal layer. In the medium term these alterations could result in the destruction of the lichen thalli, thus providing a degree of

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Molecular level damages of low power pulsed laser radiation in a marine bacterium Pseudoalteromonas carrageenovora

Cited by 9 publications

References 23 publications

Visible laser and UV‐A radiation impact on a PNP degrading Moraxella strain and its rpoS mutant

Visible laser and UV‐A radiation impact on a PNP degrading Moraxella strain and its rpoS mutant

Effects of Low-Level Laser Therapy, 660 nm, in Experimental Septic Arthritis

Influence of wavelength on the laser removal of lichens colonizing heritage stone

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